J/A+A/653/A87 TOPGot sample, SEDs and CH3CN analysis (Mininni+, 2021)
The TOPGot high-mass star-forming sample.
I. Methyl cyanide emission as tracer of early phases of star formation.
Mininni C., Fontani F., Sanchez-Monge A., Rivilla V.M., Beltran M.,
Zahorecz S., Immer K., Giannetti A., Caselli P., Colzi L., Testi L., Elia D.
<Astron. Astrophys. 653, A87 (2021)>
=2021A&A...653A..87M 2021A&A...653A..87M (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region ; Interstellar medium ; Radio lines
Keywords: astrochemistry - ISM: molecules - stars: formation - stars: massive
Abstract:
The TOPGot project targets a sample of 86 high-mass star-forming
regions in different evolutionary stages from starless cores to ultra
compact HII regions. The aim of the survey is to analyze different
molecular species in a statistically significant sample to study the
chemical evolution in high-mass star-forming regions, and identify
chemical tracers of the different phases. In the first paper we
present the sample and analyze the spectral energy distributions
(SEDs) of the TOPGot sources to derive physical parameters. We also
use the MADCUBA software to analyze the emission of methyl cyanide
(CH3CN), a well-known tracer of high-mass star formation. The
emission of the CH3CN(5K-4K) K-transitions has been detected towards
73 sources (85% of the sample). The emission of CH3CN has been
detected towards all evolutionary stages, with the mean abundances
showing a clear increase of an order of magnitude from high-mass
starless-cores to later evolutionary stages. We found a conservative
abundance upper limit for high-mass starless cores of
XCH3CN<4.0x10-11, and a range in abundance of
4.0x10-11<XCH3CN<7.0x10-11 for those sources that are likely
high-mass starless cores or very early high-mass protostellar objects.
In fact, in this range of abundance we have identified five sources
previously not classified as being in a very early evolutionary stage.
The abundance of CH3CN can thus be used to identify high-mass
star-forming regions in early phases of star-formation.
Description:
Tables containing the coordinates of the sources, the physical
quantities derived from the flux densities and the fitting of the SEDs
(Tdust, N(H2), Mass, Luminosity, L/M), and the results of the fit of
the transitions of CH3CN(5K-4K).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 77 86 Coordinates, velocity, distance and evolutionary
classification of the sources
table4.dat 53 86 Results of the SEDs fitting
table5.dat 53 86 Mass, luminosity and L/M
table6.dat 102 86 Results of the fit of CH3CN
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Index [1/86] Source index
4- 17 A14 --- Name Source name
19- 20 I2 h RAh Right ascension (J2000)
22- 23 I2 min RAm Right ascension (J2000)
25- 28 F4.1 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 40 F4.1 arcsec DEs Declination (J2000)
42- 47 F6.2 deg GLON Galactic longitude
49- 53 F5.2 deg GLAT Galactic latitude
55- 58 F4.1 kpc Dist Heliocentric distance
60 A1 --- r_Dist Flag for distance reference (1)
62- 64 A3 --- Flag [yes -] if "yes" the distance ambiguity is not
resolved and the distance given is the d_near
67- 71 F5.1 km/s Vlskr LSKR velocity
73- 77 A5 --- Evol Evolutionary phases (given only for sources
in Sub-Sample I)
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Note (1): Distance reference as follows:
- = Elia et al. (2017MNRAS.471..100E 2017MNRAS.471..100E, Cat. J/MNRAS/471/100)
a = Molinari et al. (1996A&A...308..573M 1996A&A...308..573M, Cat. J/A+A/308/573)
b = Fontani et al. (2011A&A...529L...7F 2011A&A...529L...7F)
c = Faundez et al. (2004A&A...426...97F 2004A&A...426...97F, Cat.J/A+A/426/97)
d = Sridharan et al. (2002ApJ...566..931S 2002ApJ...566..931S)
e = Hill et al. (2005MNRAS.363..405H 2005MNRAS.363..405H, Cat. J/MNRAS/363/405)
f = Immer et al. (2019A&A...632A.123I 2019A&A...632A.123I)
g = Zhang et al. (2009ApJ...693..419Z 2009ApJ...693..419Z)
h = Pandian et al. (2009ApJ...706.1609P 2009ApJ...706.1609P)
i = Mege et al., in prep.
j = Sanchez-Monge et al. (2013A&A...550A..21S 2013A&A...550A..21S, Cat. J/A+A/550/A21)
k = Sanchez-Monge et al. (2008A&A...485..497S 2008A&A...485..497S)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Index source index
4- 17 A14 --- Name source name
19 A1 --- Flag1 [Y-] flag indicating the sources for which the
Hi-GAL (Molinari et al. 2010)
maps at 70/160/250/350/500 micron were
available
21- 23 I3 --- Flag2 [850/870]?=- flag indicating if the SED has
been completed using the maps at 870 micron
(ATLASGAL- Schuller et al. 2009)
or 850 micron (SCUBA Legacy Catalog,
Di Francesco et al. 2008)
25- 31 E7.2 cm-2 NH2 Column density of H2 from the fitting of
the SED
33- 39 E7.2 cm-2 e_NH2 Error on NH2
41- 42 I2 K Tdust Dust temperature from the fitting of the SED
44- 45 I2 K e_Tdust Error on Tdust
47- 50 F4.1 arcsec theta Diameter of the source at 250 micron
52- 53 A2 --- f_theta [R NR V -] Flag for theta (1)
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Note (1): Flag for theta as follows:
R = resolved
NR = not resolved and the value assumed is 23.9"
V = value more uncertain, derived from the estimate of the dimension of
the half-maximum contour
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Index Source index
4- 17 A14 --- Name Source name
19- 22 I4 Msun Mass ?=0 Mass
24- 27 I4 Msun e_Mass ?=0 Error on Mass
29- 36 F8.1 Lsun Lum ?=0 Luminosity
38- 44 F7.1 Lsun e_Lum ?=0 Error on Luminosity
46- 49 F4.1 [Lsun/Msun] logL/M ?=0 log10 of luminosity-to-mass ratio
51- 53 F3.1 [Lsun/Msun] e_logL/M ?=0 Error on log(L/M)
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Index Source index
4- 17 A14 --- Name Source name
19 A1 --- Det [YNab] Detection of at least one
transitions of CH3CN(5K-4K) (1)
21- 24 A4 --- Range Range of K-transitions detected (2)
26- 30 F5.2 [cm-2] logN(CH3CN) ?=0 log10 CH3CN column density not
corrected for beam-dilution effect
32- 35 F4.2 [cm-2] e_logN(CH3CN) ?=0 error on logN(CH3CN) beam-diluted
37- 44 F8.2 [cm-2] logNs(CH3CN) ?=0 log10 CH3CN column density corrected
for the beam-dilution effect
46- 49 F4.2 [cm-2] e_logNs(CH3CN) ?=0 error on logNs(CH3CN)
51- 52 I2 K Tex ?=0 excitation temperature Tex
54- 55 I2 K e_Tex ?=0 error on Tex
57- 59 A3 --- f_Tex [fix -] Flag for Tex:
fix = parameter fixed during fitting
61- 64 F4.2 km/s FWHM ?=0 FWHM [km/s]
66- 69 F4.2 km/s e_FWHM ?=0 Error on FWHM [km/s]
71- 73 A3 --- f_FWHM [fix -] Flag for FWHM:
fix = parameter fixed during fitting
75- 80 F6.1 km/s Vel ?=0 Velocity from the lines fitting
82- 87 F6.2 [-] logX(CH3CN) ?=0 log10(X_CH3CN): abundance of CH3CN
89- 92 F4.2 [-] e_logX(CH3CN) ?=0 Error on log10(X_CH3CN)
94- 97 F4.2 --- alpha ?=0 Virial parameter alpha
(alpha = Mvir/Msed)
99-102 F4.2 --- e_alpha ?=0 Error on alpha
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Note (1): Detection flag as follows:
Y = detection of at least one transitions of CH3CN(5K-4K)
N = mo detection
a = G028--C3(MM11) was not observed in these frequencies
b = G031.41+0.31 transitions detected, but we were not able to perform a
reliable fit.
Note (2): Range 0-1c: K=1 component >3σ and K=0 component between
2.5σ and 3σ.
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Acknowledgements:
Chiara Mininni, chiara.mininni.astro(at)gmail.com
(End) Patricia Vannier [CDS] 28-Jul-2021